Extra Field For WordPress Registration

Extra field on Registration Form

/* Showing the extra field on the registration form */

add_action('register_form', 'new_register_field');
function new_register_field() {
?>
    <p>
        <label for="first_name"><?php _e('First Name') ?><br />
        <input type="text" name="first_name" id="first_name" class="input" value="<?php echo esc_attr($_POST['first_name']); ?>" size="25" tabindex="20" />
        </label>
    </p>
    <p>
        <label for="last_name"><?php _e('Last Name') ?><br />
        <input type="text" name="last_name" id="last_name" class="input" value="<?php echo esc_attr($_POST['last_name']); ?>" size="25" tabindex="20" />
        </label>
    </p>
<?php
}

/* Save those extra filed on the user profile area*/

add_filter('pre_user_first_name', 'user_first_name_wlx');
add_filter('pre_user_last_name', 'user_last_name_wlx');

function user_first_name_wlx($first_name) {
    if (isset($_POST['first_name'])) {
        $first_name = $_POST['first_name'];
    }
    return $first_name;
}

function user_last_name_wlx($last_name) {
    if (isset($_POST['last_name'])) {
        $last_name = $_POST['last_name'];
    }
    return $last_name;
}